Broadband quasi-Chebyshev bandpass filters with multimode stepped-impedance resonators (SIRs)

Yi-Chyun Chiou, Jen-Tsai Kuo, Eisenhower Cheng
2006 IEEE transactions on microwave theory and techniques  
Planar broadband bandpass filters of order up to 9 are synthesized based on the multimode property of stepped-impedance resonators (SIRs). Based on the transmission line theory, the modal frequencies of the SIRs are calculated based on the impedance and length ratios of its hi-and lowsegments. In the synthesis, the SIR coupling schemes are determined by the split mode graphs. Using one, two, two, three, and three dual-or triple-mode SIRs, quasi-Chebyshev filters with four, six, six, eight, and
more » ... ine transmission poles, respectively, are synthesized with a fractional bandwidth (BW) 1 = 50%. Emphasis is placed not only on designing the I/O coupling structures for matching the external ( ext ) and the circuit BW, but also on matching the resonant peaks of the circuit with the nominal Chebyshev poles. Measured results of experimental circuits show good agreement with simulated responses.
doi:10.1109/tmtt.2006.879131 fatcat:na5iirxvyrhyxp74ctltkcwaeq